FIREFIGHTERS searched through the blazing wreckage of a Great Lever factory after an explosion ripped off part of the roof.

More than 35 firefighters, including officers wearing special chemical incident suits, were called to Civil Engineering and Building Maintenance firm Trescon at noon today.

The emergency services feared workers may have been trapped inside the plant and a desperate search of the devastated plant was under way.

Police sealed off both ends of Weston Street and Viking Street was also closed as a precautionary measure.

Two ambulances were on standby in case anyone was seriously injured in the blast.

Fire fighters were taking all possible precautions in case chemicals that may have been stood in the building had spilled out and leaked into the drainage system.

They did not know what kind of chemicals, if any, are still in the building.

And at one stage police brought sniffer dogs to the scene but they were not needed as the hunt for blast victims continued.

Residents of Weston Street, whose properties face the factory said they had heard a succession of four loud bangs at noon. One eyewitness who works at E Barnett Brokers said that flames from the explosion were as high as a house.

Weston Street homeowner Rubina Ahmad heard the bangs just after noon and came rushing to the front door.

Mrs Ahmad immediately rushed acorss the road to help an elderly neighbour from her house which is located right next door to the premises.

Mr Ahmad who has lived there for more than 30 years said: "This was the second explosion at the site within 10 years. On the last occasion residents were evacuated to Burnden Park overnight."

She said: "We don't really know what is stored in there but it is quite worrying living so close."

Police were waiting for the key holder of the premises to arrive at time of going to press.

Supt Don Brown, of Bolton Police, confirmed that officers had sealed off nearby streets and Health and Safety experts were at the scene.